1. Field of the Invention
The present invention relates generally to solar cells, and more particularly but not exclusively to solar cell fabrication processes and structures.
2. Description of the Background Art
Solar cells are well known devices for converting solar radiation to electrical energy. They may be fabricated on a semiconductor wafer using semiconductor processing technology. Generally speaking, a solar cell may be fabricated by forming p-doped and n-doped regions in a silicon substrate. Solar radiation impinging on the solar cell creates electrons and holes that migrate to the p-doped and n-doped regions, thereby creating voltage differentials between the doped regions. The side of the solar cell where connections to an external electrical circuit are made includes a topmost metallic surface that is electrically coupled to the doped regions. There may be several layers of materials between the metallic surface and the doped regions. These materials may be patterned and etched to form internal structures. It is important to etch these materials in a way that would not compromise the operability and performance of the solar cell.